Empty alt text is not missing alt text

Run almost any website audit and you will find a line like "84 images missing alt text". It sounds like a clear job: go and write 84 descriptions. Before you do, check what the tool actually counted. Quite often it has counted images that are marked up correctly.

Two things that look the same to a careless tool

Alt text is the description of an image in the page's code. Screen readers read it aloud, and search engines use it to understand the image. There are two different ways an image can end up without a description:

• <img src="team.jpg">: no alt attribute at all. This is the real problem.
• <img src="divider.svg" alt="">: an empty alt. This is deliberate. It tells assistive technology the image is decorative and should be skipped.

The W3C's accessibility guidance is plain about it: for decorative images, "a null (empty) alt text should be provided (alt="") so that they can be ignored by assistive technologies, such as screen readers." And leaving the attribute out is worse, because "some screen readers will announce the file name of the image instead."

Why "fixing" it makes the page worse

If a tool counts alt=""as missing and you follow its advice, you end up writing descriptions for dividers, background shapes and icons that sit next to a text label. A screen reader user now hears "decorative swirl" and "arrow icon" between every paragraph. You spent the time and made the page harder to use.

Some website platforms, WordPress among them, write alt="" on an image automatically when nobody entered a description, so a site can carry a large number of these without anyone choosing to. Some of them will be decorative and correct. Some will be real photographs that should have a description. The number in the audit does not tell you which.

How to check your own site

1. Open a page, right-click an image the audit flagged and choose Inspect.
2. Look at the <img> tag. If there is no alt at all, it needs one. If it says alt="", ask one question: does this image carry information a visitor would miss without it?
3. If yes (a photo of your team, a chart, a product), write a short description. If no (a pattern, a divider, an icon beside its own label), leave it empty.

The wider point

An audit number is only as good as the rule that produced it. Before you act on a count, open two or three of the pages it points to and look. It takes a few minutes, and it is the difference between fixing a problem and creating one.